This invention relates to biometric sensing of human beings and other animals using wearable devices. We disclose herein a type of antenna useful, for example in the invention disclosed in WO213118121 titled “A microwave contactless heart rate sensor.” The entire contents of WO/2013/118121 and U.S. provisional application 62/083,981, filed Nov. 25, 2014 titled “Systems, Apparatuses and Methods for Biometric Sensing Using Conformal Flexible Antenna”, are incorporated herein by reference.
It has been shown previously that radar technology may be used to estimate heart rates of humans or animals. For example, WIPO Patent Application WO/2013/118121, titled “A Microwave Contactless Heart Rate Sensor,” filed on Feb. 7, 2013, and the entire contents of which is incorporated by reference herein, discloses an antenna that radiates radio frequency (RF) fields into tissues.
U.S. Pat. No. 3,031,665 describes a broadband magnetic antenna incorporating a ground plane directing the radiated energy only in one direction. The antenna disclosed in U.S. Pat. No. 3,031,665 is an rigid slot type antenna that has two parallel slots with an additional spacer slot.
The antenna for UWB (Ultra Wide Band) communication described in “A Microstrip-Fed Ultra-Wideband Slot Antenna”, Antennas and Propagation Society International Symposium, APSURSI '09, IEEE, 2009, is bidirectional and rigid.